Abstract

A backup cipher to the Advanced Encryption Standard is
reviewed while a Twofish is recommended as the backup
algorithm. The AES and Twofish are compared vis -à-vis
National Institute of Standards and Technology’s selection
criteria of the AES – general security, implementation of
security, software performance, smart card performance,
hardware performance and design features as we show that
Twofish complements the AES. General Security and its
implementation are the most significant aspects of the
selection criteria; and it is shown that Twofish is a stronger cipher.